The present invention relates generally to the effectuation of a communication service in a radio communication system, such as a cdma2000 or other cellular, direct-sequence, spread-spectrum system. More parts the present invention relates to apparatus, and an associated method, by which to allocate communication resources to effectuate the communication service at a selected quality level.
In a cellular system, if communication resources at a serving cell are determined to be insufficient to effectuate the communication service, communication resources are borrowed from another, e.g., adjacent cell. The communication resources for more than one cell are thereby allocated to provide for the effectuation of the communication service at the selected quality level.
A communication system is formed, at a minimum, of a transmitting station and a receiving station which are interconnected by a communication channel. Communication signals generated by the transmitting station are transmitted upon the communication channel to be received at the receiving station.
A radio communication system is a communication system in which at least a portion of the communication channel is formed of a portion of the electromagnetic spectrum. Communication mobility is permitted to be increased as a fixed, or hard-wired, connection is not required to be formed between the transmitting and receiving stations.
A cellular communication system is exemplary of a radio communication system. A subscriber to a cellular communication system, when positioned at almost any location throughout an area encompassed by the network infrastructure of the cellular communication system, is able to communicate by way of a mobile terminal.
The network infrastructure of an exemplary cellular communication system includes spaced-apart, fixed-site base stations which include transceivers. In such an exemplary system, each fixed-site base station defines a cell. As the mobile terminal used by the subscriber to communicate with another communication station travels between cells of the system, uninterrupted communication is possible by handing-over communications from one base station to another.
While various standards have evolved pursuant to which cellular communication systems are constructed, advancements in digital technology have permitted the development of standards, and implementation of systems capable of more efficiently utilizing the bandwidth available for such systems. Also, such advancements have permitted the introduction of communication services previously unavailable in such systems. For instance, advancements in digital communication techniques have been used in various cellular communication standards, and communication systems have been installed pursuant to such standards. One such standard, referred to as a cdma2000 standard, pertains to a cellular, spread-spectrum system.
A multimedia service, for instance, is exemplary of a new type of communication service permitted in a cdma2000 system, as well as various other cellular communication systems. A multimedia service is, however, relatively bandwidth-, and otherwise resource-, consumptive. Various other communication services are similarly also resource-consumptive.
To properly effectuate a communication service at a selected level of quality, e.g., a QoS (quality of service), level adequate levels of communication resources must be allocated for the performance of the communication service at the selected level of quality.
Most simply, if the communication resources are not available at a serving cell to effectuate the communication service at the selected quality level, permission to attempt to effectuate the communication service can be refused. But, the availability of communication resources is dynamic in that the availability of such resources is susceptible to change during performance of the communication service. If the availability of communication resources drops below a minimum threshold during the performance of the communication service, refusal to permit continued performance of the communication service would result in the abrupt termination of the service.
Proposals also have been set forth by which to lessen the service quality level by which to effectuate the communication service in an orderly manner if the available communication resources are, or become, unavailable at a desired level. Such a plan lessens the likelihood that performance of a communication service shall be abruptly terminated if available communication resources are reduced during performance of the communication service. Also, such a plan increases the likelihood that the communication service shall be permitted to be performed, albeit at a less-than-desired quality level.
Different cells of a cellular communication system, however, might have different levels of communication resources available at a particular time. And, a communication service is sometimes implementable at a selected one of more than one available cells. Communication resources unavailable at one cell to perform the communication service might be available at another of the available cells.
If a manner could be provided by which to utilize communication resources available at more than one cell, together to provide the resources needed to perform a communication service at a selected quality level, improved system performance would result.
It is in light of this background information related to wireless communications that the significant improvements of the present invention have evolved.
The present invention, accordingly, advantageously provides apparatus, and an associated method, by which to allocate communication resources in a radio communication system, such as a cellular communication system, to effectuate a communication service at a selected quality level.
When a communication service is to be performed, a determination is made as to whether communication resources are available at a serving cell to effectuate the communication service. If adequate communication resources are determined to be available at the serving cell, the necessary amount of resources are allocated to effectuate the communication service, and performance of the communication service is commenced utilizing communication resources of only the serving cell. If, however, adequate amounts of communication resources are determined not to be available at the serving cell to effectuate the communication service at the selected quality level, communication resources are borrowed from another cell, if possible, such that the communication resources of the serving cell together with the communication resources of the additional cell are together of an amount to permit the effectuation of the communication service at the selected quality level.
Determinations are made both during set-up of communications as well as during performance of the communication service. If, for instance, communication resources are available at the serving cell during communication set-up, performance of the communication service is commenced utilizing only the resources at the serving cell. If, during performance of the communication service, the communication resources at the serving cell become insufficient to perform the communication service at the selected quality level, resources are borrowed, if possible, from another cell to permit continued performance of the communication service at the selected quality level.
In one aspect of the present invention, a manner is provided for the network infrastructure of the cellular communication system to determine whether communication resources are available at a serving cell to permit the effectuation of a communication service at a selected quality level. If the required amount of communication resources is determined to be available at the serving cell, a request is made to utilize only the resources at the serving cell to effectuate the communication service. If, conversely, a determination is made that resources are not available at the serving cell to effectuate the communication service at the selected quality level, a request is made to borrow communication resources from another cell so that, together, communication resources of the serving cell and the additional cell provide the communication resources required to effectuate the communication service at the selected quality level.
The cellular communication system forms, for instance, a spread-spectrum system, generally such as that defined in the cdma2000 standard. In an aspect of the present invention, the system is further operated alternately in a non-shared mode and a shared mode relative to a particular communication service with a particular mobile station. When communication resources are available at the serving cell to perform the communication service, the system is operated in the non-shared mode. The non-shared mode includes a non-soft-handover mode and a soft-handover mode. In a conventional soft-handover mode, forward link signals are provided to two or more base stations and transmitted from such base stations. When, conversely, communication resources are borrowed from the additional cell so that communication resources are combined from at least two cells to provide the communication resources to effectuate the communication service, the system is operated in the shared mode. In this mode, a portion of the communication service is provided at the serving cell and another portion of the communication service is provided at the additional cell. Thereby, signals transmitted at the serving cell and at the additional cell are dissimilar.
In another aspect of the present invention, apparatus is provided to a mobile station to permit operation of the mobile station in both the non-shared mode and also the shared mode. The mobile station includes a rake receiver having rake fingers. When the mobile station is operated in the soft-handover mode of the non-shared mode, the rake fingers receive indications of signals transmitted by different base stations on a forward link. When operated in the soft-handover mode of the non-shared mode, the signals transmitted by the different base stations are of common values. In this mode of operation, the rake fingers are coupled to a symbol combiner at which the symbols of the signals detected by the different rake fingers are combined together. Thereafter, the combined signals are processed by other radio circuitry of the mobile station. If, conversely, the system is operated in the shared mode, different signals, representative of different portions of the communication service are formed and transmitted by the different base stations. When operated in the shared mode, the rake fingers are again coupled to receive signals generated by different ones of the base stations. Because the different ones of the base stations transmit dissimilar signals, the rake fingers are not coupled to a symbol combiner, but, rather, the signals received from different ones of the rake receivers are separately processed.
In one implementation, request for service initiation is generated by a mobile station. The request is transmitted upon a reverse link to a serving base station system. A determination is made at the serving base station system as to whether resources are available thereat to permit the effectuation of the requested communication service. If not, the mobile station is ordered to measure signal strength levels of pilot signals generated at neighboring cells. The measurements are made, and the mobile station returns to the serving base station system indications of the signal strength measurements.
If a measured signal strength of a pilot signal generated at a neighboring cell is at least of a threshold value, a request is made by the serving base station system to the base station system associated with the pilot signal as to whether communication resources are available at the other base station system to be borrowed to effectuate the requested communication service. If so, resources are assigned from the other cell along with the serving cell, together to provide the resources to effectuate the communication service. Traffic channel assignments associated with each of the cells is provided to the mobile station, and serving and shared traffic channels are established with respective base station systems. Thereafter, performance of the communication service is commenced. Thereby, a manner is provided by which to insure better that a communication service shall be effectuated at a selected level of quality.
In these and other aspects, therefore, apparatus, and an associated method, is provided for a radio communication system. The communication system includes a serving cell and at least one additional cell. Each of the serving cell and the at least one additional cell is defined by a base station selectably capable of communicating with a mobile station pursuant to a communication service. The communication service requires allocation of a selected amount of system resources to effectuate the communication service. The selected amount of system resources is allocated, if possible, to effectuate the communication service. A determiner is coupled to receive communication indicia of communication between the mobile station and the base station defined in the serving cell, and also between the mobile station and a base station defining at least one of the at least one additional cell. The determiner is operable responsive to the communication indicia to determine whether the selected amount of the system resources are available at the serving cell to effectuate the communication service. A requestor is operable responsive to determinations made by the determiner. The requestor requests allocation of the selected amount of system resources at only the serving cell if the determiner determines the selected amount of system resources to effectuate the communication service is available at the serving cell if the determiner determines the selected amount of system resources to effectuate the communication service is not available at the serving cell, the requester requests allocation of system resources at the serving cell and at a selected additional cell of the at least one additional cell. The system resources at the serving cell and at the selected additional cell together form the selected amount of system resources.
A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawings which are briefly summarized below, the following detailed description of the presently-preferred embodiments of the invention, and the appended claims.